This is on a 1998 z28 M6 with bolt ons and BTR stage two NA cam. Do you know what would cause the control module voltage get 17v at idle when my battery and alternator are putting out about 14.5v?
I measured voltage across the +- on the battery, the negative side of the battery to the ALT post on the driver's side, and I've only logged the control module.
Some symptoms I'm seeing are high idle, fuel level sensor circuit high voltage DTC and non functioning fuel gauge, and TPS voltage in the 1.4v range with the throttle closed at idle. With the key on engine off TPS is seeing .61v and my fuel gauge works.
So far I've tested the TPS, battery, alternator, and cleaned every ground I could find. It's puzzling to me how the PCM is seeing a higher voltage than what's being put out by the battery or alternator. Any ideas?